Oscillatory flow bioreactor operating at high solids loading for enzymatic hydrolysis of lignocellulosic biomass

Abstract

Bioreactor technology applied to enzymatic hydrolysis has been studied to overcome the main limitation of enzymatic hydrolysis. This work presents the application of an oscillatory flow reactor (OFR) for enzymatic hydrolysis of lignocellulosic biomass at high solids loading [> 15% (w/v)]. OFR consists of a tubular reactor with periodical constrictions where vortices are created due to the oscillating flow determined by frequency and amplitude. This can be favorable for enzymatic hydrolysis as efficient mixtures can be accomplished at low shear rates. OFR batch operation was tested at 18% (w/v) to evaluate the amplitude (2 6 mm) and frequency (2 4 Hz) conditions that best fit the process using hydrothermally pretreated corncob and low enzyme dose. The conditions tested demonstrated a positive effect on the process, where at an amplitude of 6 mm and frequency of 4 Hz, an increment of 2434% in productivity was observed. Then, three different fed-batch strategies were tested achieving 25% (w/v) solid loading where up to 170.0 g/L of glucose was obtained representing 97% saccharification yield. This novel contribution using OFR at high solids loading is crucial as advances in lignocellulosic biotransformation technology are still in demand to achieve efficient and economically feasible processes.